Remove deprecated Error::description

Error descriptions are soft-deprecated
since 1.27.0, and hard-deprecated since
1.42.0.

MSRV is 1.36.0 so well above the
1.27.0 bound.

See also rust-lang/rust#66919

src/error.rs

@@ -90,22 +90,22 @@ impl From<std::io::Error> for GameError {
 
 impl From<toml::de::Error> for GameError {
     fn from(e: toml::de::Error) -> GameError {
-        let errstr = format!("TOML decode error: {}", e.description());
+        let errstr = format!("TOML decode error: {}", e);
 
         GameError::ConfigError(errstr)
     }
 }
 
 impl From<toml::ser::Error> for GameError {
     fn from(e: toml::ser::Error) -> GameError {
-        let errstr = format!("TOML error (possibly encoding?): {}", e.description());
+        let errstr = format!("TOML error (possibly encoding?): {}", e);
         GameError::ConfigError(errstr)
     }
 }
 
 impl From<zip::result::ZipError> for GameError {
     fn from(e: zip::result::ZipError) -> GameError {
-        let errstr = format!("Zip error: {}", e.description());
+        let errstr = format!("Zip error: {}", e);
         GameError::ResourceLoadError(errstr)
     }
 }
@@ -119,7 +119,7 @@ impl From<DecoderError> for GameError {
 
 impl From<image::ImageError> for GameError {
     fn from(e: image::ImageError) -> GameError {
-        let errstr = format!("Image load error: {}", e.description());
+        let errstr = format!("Image load error: {}", e);
         GameError::ResourceLoadError(errstr)
     }
 }
@@ -156,7 +156,7 @@ where
 
 impl From<gfx::CombinedError> for GameError {
     fn from(e: gfx::CombinedError) -> GameError {
-        let errstr = format!("Texture+view load error: {}", e.description());
+        let errstr = format!("Texture+view load error: {}", e);
         GameError::VideoError(errstr)
     }
 }